This invention relates to graders and rotary tillers that have cutting blades arranged to revolve about vertical axes, and particularly to precision road graders that have conveyors and leveling blades mounted to follow the rotary cutters for moving pulverized soil laterally and for leveling a desired smaller amount of soil within the newly cut subgrade.
In preparation of subgrades for sidewalks or for roadways, soil to be removed is pulverized by implements such as those having tines that revolve about horizontal axes, and then the pulverized soil is removed by shovels or blade graders. A thin layer of pulverized soil may be desirable at the bottom of the subgrade over which the concrete is to be poured, and this layer of pulverized soil may be leveled at the desired height by blades of simple graders. A usual tilling apparatus for pulverizing the soil has tines revolving about horizontal axes, and the tines to remove clods from the bottom of the subgrade so that the surface of the undisturbed soil is rough. Equipments that have had cutters mounted on vertical axes generally had downwardly directed spikes to be revolved about the axes and therefore did not slice the bottom of the subgrade evenly, and separate equipments were required for removing soil and smoothing the subgrade.